1. Field of the invention
The present invention relates to a method for localizing sound image of a reproducing sound outside speakers when audio signals recorded on an audio source (recording media) for stereophonic reproduction, such as a CD produced for the purpose of stereophonic reproduction are reproduced by right and left speakers, more particularly to a method for moving the sound image caused by the reproducing sound up and down, and bringing away and near the sound image from the line connected right and left speakers.
2. Description of the Related Art
Conventionally, various technique of localizing sound image in stereophonic listening with right and left speakers for reproduction set have been proposed and tried.
It is said that people generally sense a position of a sound source to be listened, that is to say, the position from the view of a listener about up and down, right and left, front and rear of the sound source by listening with both ears. Therefore, in the stereophonic reproduction, it is thought that the listener can listen to the reproducing sound from the right and left speakers just like sound from a real sound source by applying convolution arithmetic manipulations of real-time to the audio signals, in the sound source, optionally input according to the required transfer function to reproduce the audio signals for localizing the sound source in auditory sense by the reproducing sound from the right and left speakers.
Above-mentioned sound image localization system in stereophonic listening is based on a concept that the sound of the sound source input at random place can be localized in auditory sense by the reproducing sound for stereophonic listening by producing the transfer function to provide outer head sound image localization, in auditory sense, as of the listener listened just like at the place where the real sound source is located, from an expression showing output electrical information of a small microphone to input a pseudo sound source and an expression showing an output signal of an earphone, and by applying the convolution arithmetic manipulations of real-time to optionally input sound signals for reproducing and outputting by means of the transfer function. There is a problem that the system requires a large amount of software for the arithmetic manipulations and a large scale of hardware.
In the invention, considering a problem that the sound image localization technique in the above-mentioned conventional stereophonic listening requires a large amount of software and a large scale of hardware, it is an object to provide a method capable of localizing the sound image of the reproducing sound outside the right and left speakers by processing and controlling the audio signals for stereophonic reproduction which allows the sound image localization outside the right and left speakers using a very concise hardware architecture without such a problem and by reproducing the controlled audio signals.